Ignition and priming compound



- Patented Oct.11,1938

IGNITION AND PRIMING COMPOUND Mario Palmieri, South Glastonbury, Conn.,assignor of one-half to Samuel D. Ehrlich, Glastonbury, Conn.

No Drawing. Application February 12, 1936,

' Serial No.'63,555

10 Claims.

This invention relates to that class of compounds adapted for use as anigniting, priming or heating means for explosives.

More particularly the compounds are designed for igniting blasting caps,for igniting thermite and for other purposes such as delays for shells,delay trains for delay electric blasting caps, etc.

An object of the invention is to provide an improved composition thatwill be stable and safe to handle under all conditions and may be madehaving varying degrees of sensitivity as required for differentparticular services.

Another object of the invention is to provide a composition of the abovetype that will be nonexplosive and will not be affected by moisture orvarying temperatures and will remain effective over long periods oftime.

Another object of the invention is to provide a non-gas forming andnon-spitting composition 29 adapted to generate intense heat and adaptedfor the purpose of igniting and priming explo- With the above and otherobjects in view myv invention includes the features set forth in the 39following specification and illustrated by the specific examplesincluded therein.

Briefly and in its preferred aspect, my invention may be composed of thefollowing materials: first, a phosphide of a metal such as copper or 35zinc, or a mixture of the phosphide of each of these metals in diiierentparticular proportions for special purposes; and second, an oxidizingcompound such as potassium bichromate, barium chromate, red lead, etc.

10 The quantity of metallic phosphide may be varied from about 15% to40% and the oxidizer from 85% to 60%. The sensitivity and speed of thecomposition may be widely varied by varying the proportions ofphosphides of the zinc and 45 copper as well as other metallicphosphides, e. g., manganese phosphide, iron phosphide, nickelphosphide, cobalt phosphide, chromium phosphide, boron phosphide, etc.Also if mixtures of copper and zinc phosphide are used, greater sen- 6sitivity and speed may be obtained by larger ratios of zinc than copperphosphide. Particular services requiring highly sensitive compositionsmay be of boron phosphide. To decrease the sensitivity and speed theproportion of zinc 55 phosphide is reduced and other suitable metallicphosphides used as well as the copper. Also there may be an inertmaterial, such as iron oxide, magnesium oxide, silicates, silica, etc.added.

When a greater amount of heat is required, 6 the composition may haveadded to the sub stances referred to above an amount of finely dividedaluminum, magnesium, etc., which great- 1y increases the intensity ofthe heat generated by the combustion of the composition. A compositionincluding aluminum with the phosphide and oxidizer may be used to bestadvantage to ignite diflicultly ignitable materials such as thermite.The addition of this finely divided aluminum also has the eiiect ofincreasing the ease of ignition of the composition.

As an example of an igniting composition particularly adapted fordelayed blasting caps, squibs, etc., the composition may includeapproximately metallic phosphides and 75% potassium loichromate. Thephosphides may be approximately of zinc and about copper to give therequisite sensitivity.

A composition primarily designed for igniting thermite and similarcompounds may contain up 25 to about 10% of metallic aluminum inpowdered form, from 5% to 15% zinc phosphide, and about to of potassiumbichromate, lead or manganese oxide, barium chromate or otherinsensitive oxidizing element. To increase the sensitivity to ignitionand speed of burning there may be added red phosphorus.

In using the above described compositions wherein it is confined as inblasting caps to ignite the detonating substance such as mercuryfulminate, it is not necessary to vent the casing for the cap as noappreciable amounts of gasses are generated and therefore no pressuresare created Within the casing that would require an absorbing element ormight destroy the container or 0 prevent complete burning of thecomposition. After burning the ashes remain in compact form within thecasing or receptacle for the compoition. During combustion, ignition ofthe composition takes place uniformly and without violence.

The composition is non-explosive and is entirely safe to handle; it alsocan be granulated into pellets of any size and safely stored over longperiods of time without deterioration. 50

The choice of oxidizing means for the composition enables the rate ofburning of the composition to be controlled. Chromates and dichromatesas of potassium, barium, lead are less sensitive and result in a slowburning of the com- 55 positions in which they are employed with thephosphides. Oxides of lead such as P1030; or PbOz or manganese dioxideare more sensitive and result in a faster rate of combustion of thecomposition.

I claim:

1. A priming composition for blasting caps. and the like, comprising incombination, a metallic phosphide, and an oxidizer selected from thegroup consisting of an oxide and a chromate.

2. A priming composition for blasting caps and the like, comprising incombination a metallic phosphide, and a chromate oxidizing compound.

3. A priming composition for explosive charges comprising phosphide ofzinc and a chromate oxidizing compound.

4. A priming composition for explosive charges comprising phosphides ofzinc and copper and a chromate oxidizing compound.

5. A priming composition for igniting explosive charges comprising amixture of from to of phosphides of copper and zinc and of 85% to ofpotassium chromate.

6. A priming composition for explosive charges comprising one part of amixture of copper and zinc phosphides, and three parts of potassiumchromate, there being approximately 30% zinc phosphide and copperphosphide in the phosphide mixture.

'7. An igniting composition for thermite and the like, comprising up to10% powdered metallic aluminum, 5% to 15% Zinc phosphide, and tooxidizing compound comprising a chromate.

8. An igniting composition for thermite and the like, comprising up to10% powdered metallic aluminum, 5% to 15% zinc phosphide, and 75% to 85%oxidizing compound comprising an oxide.

9. An igniting composition for thermite and the like, comprising amixture of copper and zinc phosphides, metallic aluminum, and anoxidizing compound comprising a chromate.

10. An igniting composition for thermite and the like, comprising amixture of copper and zinc phosphides, metallic aluminum, and anoxidizing compound comprising an oxide.

MARIO PALMIIERI.

